The invention pertains to an ultra-high performance concrete produced essentially from cement, aggregate, water, fillers, and additives. The term “ultra-high performance concrete” is also used in this application for the associated concrete mix from which the concrete is produced.
When prefabricated components are used in building construction, normal concrete of strength classes C40/50-C60/75, for example, together with reinforcement of grade B500B (normal steel), is usually used. Higher-strength concretes up to strength class C100/115 are used for certain applications in the area of slender columns and highly stressed bridge components. Steel composite columns are often used for structures with very slender or highly loaded columns such as those found in parking garages, business towers, and hotel towers, for example, or for conspicuous public buildings. Nevertheless, these suffer from the disadvantage that a very large amount of steel is required, and in addition this large amount of steel leads to considerable production costs.
A concrete with a compressive strength of at least 140 N/mm2 is usually designated an “ultra-high performance concrete” (UHPC).
In addition, self-compacting concrete (SCC) and form-vibrated concrete are also known.
The previously developed ultra-high performance concretes (UHPCs) are used only rarely in practice, because these concrete mixes are extremely expensive; typically, the cost is about 10 times that of normal concrete. Conventional ultra-high performance concrete contains very expensive fillers and additives, among other things, which results in the high price. In addition, these fillers or additives must be screened with extremely high precision in order to achieve a high density (bulk density).
A disadvantage of working with ultra-high performance concrete is its stickiness, which means that it cannot be pumped in the conventional way. It is therefore usually introduced into the form by hand, which increases the amount of processing work.